1. Field of the Invention
The present invention relates to moving a head from a disk in a hard disk drive when power to the drive has terminated.
2. Background Information
Hard disk drives contain a plurality of magnetic heads that are coupled to rotating disks. The heads write and read information by magnetizing and sensing the magnetic fields of the disk surfaces. Each head is attached to a flexure arm to create a subassembly commonly referred to as a head gimbal assembly (“HGA”). The HGA's are suspended from an actuator arm. The actuator arm has a voice coil motor that can move the heads across the surfaces of the disks.
Information is typically stored in radial tracks that extend across the surface of each disk. Each track is typically divided into a number of segments or sectors. The voice coil motor and actuator arm can move the heads to different tracks of the disks.
When a drive loses power the heads are typically moved off of the disks to prevent a loss of data. For example, the heads can be moved onto a mechanical ramp. When moving the heads off disk it is desirable to maintain a relatively slow and uniform velocity profile to prevent any sudden head movement and potential damage to the actuator suspension.